Specifically interested in regards to the M4 barrel (14.5" chrome lined, 1 in 7).  I know that accuracy is affected by a variety of factors, but I'm wondering about the change in accuracy by FF alone, such as shooting identical rifles from a solid posistion with all factors being the same, excepting the free float hanguard vs. the standard M4.

Alot of dudes here are of the opinion that it does in fact improve accuracy quite a bit.  I tend to think that it isn't really relevant.  The M4 is a close in weapon, not a "reach out and touch em" rifle.  In dynamic shooting (ie, room clearing, cqb, and so forth) I don't really think that it makes any difference at all.  I think free floating really comes into play when you are doing precision shooting at greater distances 400-900 yards.  

JMO
YMMV

There's no doubt that free floating will increase the accuracy of most rifles.  How much depends on a lot of different things.

I agree that for the most part short carbine rifles are not really in need of a free floated barrel.  If I was happy with the way my rifle shot I wouldn't go out of my way to get it free floated.

That being said, when upgrading to a railed system most of the better units already free float the barrel so why fight it? It certainly won't detract from your rifle.

As always setting up a rifle is all about user preference so YMMV! [;D]

Well...


Do you shoot a lot of rapid fire, do you think your rifle's gonna heat up it's barrel and become sensitive to pressures placed on it by the handguard?

Or is your type of shooting such that it doesn't expose the barrel to much heat or external forces through the handguards?


I have an AR10 A4(non freefloated barrel) that is actually quite accurate with handloads but only when the barrel is fairly cool and I'm not putting much force on the handguard.    During accuracy testing, I can watch the groups consistently open up once the barrel heats up a certain amount.   It's hard to get a 5 shot group sometimes if the barrel has heated up too much.   With my better handloads, so long as I don't let the barrel heat up too much the gun turns in right around 1 inch 5 shot group averages.    But if I let too much heat build up into the barrel, it will open up beyond 1 inch or more.


Freefloating a handguard can REALLY help improve the consistency of the barrel's accuracy as the barrel heats up.     My freefloated accurized AR15 averages around 3/4 inch for 10 shots with little consideration to how fast I fire the 10 shots.


It is very likely that if I were to freefloat my AR10, I might not gain a whole lot in accuracy but I will gain consistency in how many shots I can fire before my AR10's groups began to open up while also making it less sensitive to the pressures placed on the handguards.

u.gun,
I agree with your comments re the AR-10A4.  Later this year we will have the opportunity to try a FF rail on our AR-10A4's should we want to - and probably I do want to !!  Early on I was surprised, no make that very surprised, that such accuracy could be gotten from the AR-10A4 with the standard chrome lined barrel and not FF.
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F. Cannibal, I mean no disrespect but it's really hard to consider accuracy and a 14.5" barrel.  However, I would venture a SWAG that perhaps as much as 1"-1.5" at 100 yds with a hot gun - all other factors being the same.  (With a 14.5" barrel I imagine you're planning on shooting mostly center-mass (center-torso) anyway.)

No disrespect taken.  Your mention of the 14.5" barrel is what prompted this question; I have no doubt that FF will increase accuracy; however, I am curious as to how much of an increase one can expect [i]out of an M4gery[/i] by free floating the barrel.

I am still debating the investment in a RAS II setup, and this accuracy issue is a pivitol point in my (self) debate.

Understand.  And you're right, accuracy should be your determining factor.  I've given my 'guess' above - for what it's worth.  I'm getting ready to send my 16" carbine to Wes Grant (mstn.biz) for him to put on a KAC FF RAS whatever that's worth.  I'm simply going on the I-know-it's-going-to-be-MORE-accurate theory !!

F.C.,
I THINK I'm right on this.  Knight's offers their SR-15 Match with a 20" barrel and FF RAS. I know their SR-15 M4 carbine, 16" barrel has the non FF RAS.  I don't believe they offer a FF RAS in a carbine length barrel.  Again, I believe but am not certain on this.  The point being that either Knight's (or more likely the military)doesn't believe in FF even a 16" barrel - if I'm right.

The RASII is an excellent rail system.  Are you debating the cost versus another unit or is it more like RAS vs RASII?

As the others have mentioned a free floated barrel is more consisant regardless of length and consistancy = accuracy.

I guess I'm a bit confused.  Other than free floating the barrel aren't the features and abilities of the RASII enough to sell the product to you?

What is the intended use of the rifle you're setting up?  What type of optics will you use. What other accesories will mount on it?  Once you figure these things our everything starts to clear up.  

5subslr5,

Knight's certainly has one, they call it the Short FFRAS product #KAC-20208. It comes in medium and long versions as well as MRE version. [:D]

I think it will help some. I like the Tactical Full Floating Phantom II. They make one for the 16", and the 20" barrel. It is fully ventilated, it is drilled and tapped for the Swan/Weaver Rails. These rails come in 2",3",4",7",and 12", and it only cost $79.95 form Http://www,fulton-armory.com.

I can't offer you any concrete scientifically conducted results but................
I haven't shot my ARs at 200 yards a whole lot. In fact the only times I have ever done it was during classes. I attended my first class and did OK at 200. I hit the silhouette every time COM. I decided that I wanted to get a rail system, primarily to mount a Surefire 900 series weaponslight. I chose a KAC RAS II. At the next class I took, I fired some groups at 200 that I was really proud of. On the order of maybe 5" using a 16" AR with an Aimpoint ML2 from a prone position lying in the dirt. Significantly better than what I shot at the first class. I realize that my sklls probably imporved somewhat, maybe I was having a good day, but I would like to think that some of the accuracy imrovement was due to the floated barrel. I probably will never test this partiuclar AR for potential accuracy by shooting it off a bench with a scope, but if I can shoot a 5" group at 200 from a field position using a red dot, I have to believe that I have a damn accurate rifle. And if the rifle is accurate at 200 yards or more, that doesn't hurt you at 20 feet. There is no reason to limit yourself just because you see a short AR as being a close quarters weapon. It can be, but it can also be much more. Let it rise to the occasion.


By the way, those groups were fired using Wolf 55 grain ammo.

Free floating will allow you to use a tight loop or hasty sling with out causing detrimental pressures on the barrel, or to rest your handguard on a support without moving your zero.

While these don't make the rifle inherently more accurate they do increase the precision 'shootability' you can wring out of your weapon.

I didnt think FF the barrel was going to do much. I was wrong. Groups in my M4 went from about about 1.25 or 1.75 moa to sub moa. So yes, it will increase your accuracy.

Some people feel like increasing accuracy on a "CQB" gun shouldnt be a real consideration, or at least not much of one. I disagree 100%. Why wouldnt you do anything you can do to increase the overall usefulness of the gun and its capabilities in a variety of environments and situations... without compromising its initial or primary role in any way shape or form?!?

The fact that you have a CQB gun that can shoot as well as many bench or bolt guns is a tremendous advantage in my opinion.

Don't you have to take off the barrel and gas block to install the FF RAS?

That sounds like a major PITA.

You do have to remove them for the FF RAS and most other FF tubes. and I agree. It is a PITA. At least initially. Once you get it on however, there is little reason to ever need to remove it.

If you still dont like the sound of that, go with the RAS II or ARMS SIR. Both FF the barrel and are drop on/take off accessories.

I agree and since most of the nice forends on the market today are going the FF route now anyway you might as well get that added benefit.  The RASII is not really more cost prohibitive than the RAS especially for the benefits gained.  I havent looked for awhile but it may even be the same price!

Frank White of Compass Lake Enginering says that free floating the barrel is the most important thing you can do to increase accuracy. He is know as one of the if not the formost expert in rifle competition accuracy.

Ammunition is the key to accuracy. If your not useing match or hand loads the point of free floating is somewhat moot!

I have heard both sides and agree both ways.  I personally don't think it matters a damn in a small carbine package, but that's just me.

YMMV  

I am in the process of testing the FF aspect on a DPMS M4 16" 1/7 pre-ban upper sold by CMMG on the EE.

I did a round test the other day using different rounds with upper as shipped (w/ oval M4 HGs) and just swapped my ARMS #45 SIR from the Colt M4 16" pre-ban 1/9 twist upper to the DPMS.

I have had this SIR on a RRA M4 post-ban 1/9 upper and compared the difference between FFing using the SIR and shooting it w/ the oval M4 handguards and the SIR made a noticeable difference, in that the groups tightened up about a 1/4" to 1/2" at 100 yards depending on the type of rounds fired through it. Remarkably some of the rounds, I'd decided the rifle didn't like, shot much better and accounted for the 1/2" improvement in group sizes, where-as rounds which the upper had shot it's tightest groups with tighten only in the 1/8 - 1/4" range. Anyhow the RRA did benefit from free-floating.

Did the same test using the Colt M4 listed above and while I cannot explain why, IT showed NO appreciable tightening from the groups fired w/ standard oval M4 handguards. Again I am at a loss to explain why not, and I fired multiple rounds of groups, w/ rifle both hot and cold as I was puzzled NOT to see the type of reduction which showed up w/ the RRA upper, but in the end I can honestly state, that if it shot tighter groups, they were too small to measure.
(these groups were shot both at 50 and 100 yards, searching for improvement)

This is why I decided to shift it (ARMS SIR)to the new 1/7 DPMS, so I could see if it would react like the RRA and tighten up, or like the Colt have NO change.

Based on what is stated above and my results, I'd say it depends entirely on the individual upper and barrel as well as other factors on whether it will or won't tighten your groups, only trial and error will tell ya. As IMO what works for some may not work for others and you are your own best judge of whether there's improvement or not.

Mike

PS: all this was done from sand-bagged or benchrester's type rests, front and rear on all rifles, as I wanted to remove as much shooter error as possible.

Yes, I am debating the cost.  



All good questions.  I avoided mentioning these things, however, because I started another thread a while back in which I asked for opinions on add-ons and the RAS II, so I wanted to avoid a duplicate thread.

At this time all I can see adding would be a forward grip, and $400 for a grip and FF is just alot of money, period.

Although new-arguy has just about convinced me to sell my TA01NSN, which could easily justify the RAS II and perhaps an Aimpoint.  We'll see.

Thanks for all the informative replies.

mr_wilson,

Interesting results in your SIR testing.  Please keep us posted on how the CMMG/DPMS upper does.

I have the same upper you have but it went straight into a SIR 50 so I never got to see how it would do with the M4 handguards.  In my initial firing and zeroing I was able to get several 3/4", 5 shot groups at 100 yards.  This was off sandbags using XM193.  I'm no match shooter so I know this rifle could probably shoot better than me. [;)]

FC,

Yes, cost is a factor, isn't it always?  I feel for you, but this is the path we've chosen with our addiction...[:D]

Wait until you decide you need a $450 Surefire to go with your new setup![:O]